1. Field of the Invention
The present invention relates to a shunt resistance type current sensor.
2. Description of the Related Art
There has been proposed a shunt resistance type current sensor in which current to be measured flows into a shunt resistor having a known resistance value in order to detect a pulse current, a large AC current or the like, and a voltage drop generated across the shunt resistor is detected, thereby measuring a magnitude of the current to be measured. For example, in a vehicle such as an automobile, a metal piece called a bus bar is sometimes used for power distribution, and a part of the bus bar corresponding to a current path is utilized as a shunt resistor. A circuit board is disposed on the bus bar. In order to detect a magnitude of the current to be measured flowing through the bus bar, the circuit board mounts a voltage detection IC, and so on for detecting a magnitude of voltage applied to the shunt resistor.
A patent literature 1 to be described below discloses a current sensor in which a bus bar is provided with a flat part, a circuit board is mounted on the flat part, and a current flowing in the bus bar is obtained based on a voltage drop in the bus bar and a known resistance value. This bus bar is provided at one end thereof with a connection part to be connected to a battery post and at the other end thereof with a connection part to be connected to a wire harness via a stud bolt. The bus bar is disposed on an upper surface of a battery at which the battery post exists.
The patent literature 1 is JP-A-2012-78328.